Bounded by the Pacific Ocean and two of the Los Angeles area’s most exclusive country clubs, the 90402 zip code would meet most definitions of prime real estate. In fact, according to a new study, it’s among the most exclusive addresses in the U.S.

It’s not about the well-heeled homeowners there, though with average home values exceeding $3 million you’ll find plenty of those. It’s about the zoning restrictions, which the study found are preventing builders from supplying the market with more homes that buyers want.

The chart reflects an analysis by Issi Romem, chief economist of BuildZoom, a San Francisco-based company that connects homeowners with building contractors.

Romem set out to identify areas where home values outstrip the construction cost of new homes, giving builders a natural incentive to put up more of them. He took the average home value in a given area and subtracted the estimated average value of the sticks and bricks. The data came from the census; the full methodology is here.

While construction costs vary from one market to another, those differences play a small part in explaining why homes are so much more expensive in some places than others, Romem said. Scarcity plays a much bigger role, he said, and high land values are partly due to zoning restrictions that limit the density of residential construction. If builders were given free rein to build all the homes they thought they could sell, the argument goes, the difference between home values and construction costs would shrink.

To that end, it’s instructive to compare land values in California cities, where restrictive land use policies have helped drive up housing prices, with those in Texas. In the metropolitan area of San Jose, the average land value per home was $931,000, according to Romem’s data; in Los Angeles, $782,000. In Houston, known for freer zoning regulations, it was $133,000.